The acute and subchronic toxic effects of the pesticide 1,2-dibromo-3-chloropropane (DBCP) and structurally-related compounds are studied from functional and mechanistic viewpoints. A reported chemo-sterilant in humans, DBCP is no longer manufactured in the U.S., but its presence in ground water and on edible imports and its illegal bulk transport into certain areas of the U.S. require its further toxicological characterization. Effects of DBCP on hepatic, renal, and reproductive functions and development are evaluated at several dose levels, after various treatment regimens and under differing conditions such as age, chemical or physical stress and the like. The mechanism of DBCP inhibition of sperm energy metabolism is being investigated.